Private baths help you on habitability and help you enormously on management, because shared-bath complaints are the largest single source of resident friction in this model. Whether they help you on licensing depends on how your jurisdiction defines the use. Some rooming house ordinances require a minimum number of fixtures per occupant and you'll clear it easily. Some define the use by the presence of shared cooking facilities, and in those places a building with no kitchen anywhere isn't a rooming house at all, it's an extended stay lodging use with a transient occupancy angle and a different tax treatment. Get the use classification in writing from the zoning administrator before you price a kitchen.
Assume you need cooking. A shared kitchen serving 12 residents is usually classified as residential rather than commercial if residents cook for themselves, which keeps you out of hood and interceptor territory in most codes, though your local health department may see it differently. Budget $35k to $70k for a room that can actually take that load: two ranges, two refrigerators, a durable floor, and enough electrical to run it. The kitchen is not your biggest number.
Your biggest number is the single meter with resistance heat. Twelve rooms of electric resistance in a 1960s motel envelope with utilities included means you're absorbing every degree every resident chooses. Pull twelve months of actual utility history from the seller or the utility, not an estimate. I've seen these come in at $150 to $250 per room per month in cold months, which takes $700 down to something that doesn't service the debt. Submetering is often impractical in that construction, so the fix is envelope work and heat pumps, which is another six figures.
The other thing to verify early is whether the state route frontage puts you under a state highway access permit for any change of use. That review has stopped motel conversions I've read about at the site plan stage.
